Stroke indicating device



June 10, 1941 L. T. STUMPF STROKE INDICATING DEVICE Filed April 27, 1940 i an A .l 'iv ll llilIII!IiI!itlilirllfalllllllilillrt 5 INVENTOR LEWIS T. STUMPF Patented June 10, 1941 UNITED STATES PATENT OFFICE STROKE INDICATING DEVICE Lewis T. Stumpf, Cleveland, Ohio Application April 27, 1940, Serial No. 332,027

4 Claims.

This invention relates to improvements in practice apparatus for use with playing clubs which are adapted to be swung. The invention relates to mechanism for measuring the intensity of a swing imparted to the club. i

My improved apparatus has been shown in conjunction with a golf club but I do not desire to be limited in the application of the improvement here disclosed except 'as required by the appended claims.

One of the objects of the present invention is to provide a simple apparatus for attachment to a club shaft wherein a weight is adapted to be moved against a spring by the centrifugal force generated while swinging the club, together with means for holding the weight in the farthest position to which it is moved so that its relative position on a scale may be determined thereby indicating the intensity of the swing.

Another object of the present invention is to provide a device which is cheaply and easily constructed and preferably also one which may readily be attached to an existing golf club, thus not requiring a special club.

Other objects and advantages of the invention will be apparent from the accompanying drawing and description and the essential features thereof will be set forth in the claims.

In the drawing, Fig. 1 is an elevational View of the lower end of a golf club equipped with m invention; Fig. 2 is an enlarged sectional view of the club of Fig. 1 showing the arrange-' ment of the parts; Fig. 3 is a further enlarged transverse sectional View taken along the line 3-3 of Fig. 2; Figs. 4 and 5 show details .of the weight and ratchet mechanism for holding the same after the club has been swung; while Fig. 6 is a detail view of the connection of the lower end of the sleeve to the shaft, showing a modification of a similar structure shown in Fig. 2.

In the various views I0 indicates a golf club shaft to which is secured the head II in the usual manner. Surrounding the shaft and spaced from it is a sleeve 12 which is closed at its upper end by a fitting lZa which is threaded or welded to the cylindrical portion l2 and provided with a central opening through which the shaft 56 extends. The lower end of the sleeve I2 is closed by a fitting I2b which has an opening in flanged extension In to accommodate the shaft I i]. A set screw I3 holds the sleeve in fixed position on shaft I6 although the same result might be accomplished in many ways. For instance a spot weld or a bit of solder would serve to anchor the sleeve I2. Within the sleeve I2 and slidable longitudinally in the annular space between the sleeve and. the shaft is a Weight I4 which in the present embodiment is a small cylindrical piece having openings in its opposite ends for sliding engagement with the shaft ID. A helical spring I5 embraces the shaft It lying between the shaft and the sleeve I2. This spring is engaged between the member I21) and the weight I4 so as to hold the weight normally in its uppermost position as viewed in the drawing.

Ratchet means is provided for holding the weight I4 in the farthermost position to which it is moved by a swing of the club against the action'of the spring I5 tending to return it. The means here shown comprises a slot I6 formed in the sleeve I2 and bearing teeth I! on its upper edge adapted to engage with teeth I8 on a small projection I4a which is fixed to the weight I I in position to project into the slot I6. The weight is provided with an extension piece Ito for manually resetting the device. It will be noted that the teeth I! and I8 are so arranged that the teeth l8 easily pass over the teeth H as the weight moves downwardly along the shaft against the spring I5, whereas the coasting teeth mutually engage to hold the weight when the spring tends to return the weight to its uppermost position. 7

As best seen in Figs. 4 and 5, the slot I6 is inclined at an angle to the axis of the shaft II] for reasons that will appear. This inclined position of the slot permits the provision of a greater number of teeth I! in a given vertical length of the sleeve I2 so as to permit a finer calibration of the device. The ratchet part I la carries teeth l8 on the side toward the teeth ll of the slot but the opposite side of part I la is smooth to coact with the smooth or lower side of the slot I6. As shown in Fig. 4, the part M11 is of less width than the slot I6 so that as the weight I4 moves downwardly during a swing of the club, the teeth I8 move away from the teeth I! permitting the smooth side of part Ha to ride along the smooth side of slot l6, thus reducing the friction of the parts as the weight It moves downwardly. Obviously the moment the weight I4 begins to move upwardly under the influence of spring I5, the teeth I1 and I8 will re-engage and hold the weight.

As shown in Fig. 6, the sleeve I2 similar in other respects to the sleeve l2 already described, may have a shoulder 20 formed at its lower end. A collar 2| is provided having sliding engage- -Fig. 6 permits relative rotation of sleeve l2 relative to theshaft to. If necessary or desirable, a small. amount of lubricant may be placed between the shoulder 20 and the collar 2| and such lubricant will be held there by the member When the device constructed according to g Mb. I Fig. 6 is in place and the club is swung, the

engagement between the smooth. side. of. the. ratchet part Ma and the smooth sideof. slot I6.,.

will tend to rotate the sleeve l2 and'I'find that this adds to the sensitiveness of, the, device.

It is thought the operation of my device will, now be apparent and it'occurs as follows: With" the parts in the position shown in Figs. 1 and 2, theclub is swung in the usual manner and the centrifugal force generatedcausesweight M to move downwardlyagainst spring l until the point-of maximumcentrifugal force is reached. As, that force decreases, spring [5 tends to return the weight Mtowardits uppermost position and at, such time theteeth I8 engage the teeth I1 and hold the, weight in the lowermost position to-which ithas been moved by the centrifugal force generated. Ifv desired, a scale may be provided along the upper edge of slot It as indicated at l9, Fig; 4.

Since-a .device' of thissort is of greatest interest to'a golfer in connection with a club with a.wooden head, such as is generally used for driving a ball from atee, I have provided a device which is particularly easy to install in a club of this sort. Byremoving the screws, I la, the head ll may be slipped. off the shaft Ill and my indicating device. may be slipped upward on the shaft and. secured in position by set screw it afterwhich the head may be again secured to the shaft. Thus the device may be applied to a standard clubby anyone without special tools or without changing. the standard club in any way, When'the, device is used on adriving club it may be desirableto, mark the scale 19 in terms of approximate yardage which would be produced by a swing of the intensity indicated.

My indicating. device may also be attached to ironsbysimply driving out the brass pin or other fastening, means. whichholds the head on the shaft, placing the device in proper position on the. shaft as shown in Fig. 2, and then replacing the -;clubihead. Insuch use with irons a golfer mayreadily determine the proper indication on the scale to drive the ball a desired distance With the iron. It will-be noted thatthe slot I6 is helical in form' as I find this gives more accurate indications. Therefore, the teeth [8 on the weight M 'are arranged at-the helixangle andthe portion Ida extends into the slot ,lfirand. slides easily alongthis slot when the club is swung.

What I claim is: 1.. In combination with a club shaft, a. sleeve mounted concentrically on said shaft and rigidly secured thereto against longitudinal movement therealong, said sleeve having an internal diameter greater than the external diameter of said shaft, an annular weight slidably embracing said shaft in the space between said shaft and sleeve, a helical spring surrounding said shaft in the space between said shaft and sleeve and urging said weight toward one end of said sleeve, said sleeve being provided with a slot, and. a ratchet device comprising parts-on said weight and on said sleeve at the edge of said slot arranged to permit free movement of said weight away from said one end of said sleeve and arranged to hold said. weight. against the action of said spring tending, to. move said weight toward said one end of'said' sleeve.

' 2: In, combination with a club shaft, a sleeve slipped on said shaft and rigidly secured thereto against-longitudinal movement therealong, said sleeve havingan internal diametergreater than the, externaldiameter of said-shaft, an annular weight slidably embracing said shaft in the space between said shaft and sleeve, a helical spring.

surrounding said shaft in'thespace between said shaft and sleeve and urgingsaidweight toward one end of said sleeve; said sleeveibeingprovided with a-helical slot'havingratchet teethalong the edge thereof nearer said one end, ,a. ratchet member secured to said weightv andv extending into said 'slot, and the teeth of 'saidslot andzsaid ratchet me-mberbeing. arrangedtopermit free movement of said weightawayfrom said one .end of said sleeve andarrangedyto hold said weight againsttheaction of'said spring tending .to move said weight toward. said one; end. of said sleeve;

3. In combinationwith a.-clubishaft, a sleeve mounted concentrically; on said shaft and rigidly secured thereto. against longitudinal movement therealong, said sleeve having an internal diameter-greater thanthe external diameter of said shaft, an annular weight slida'bly embracing said shaft in the spacebetweensaid shaftand sleeve, a helical spring. surrounding said shaft in the space between said shaft and. sleeve and .urging said weight toward oneendof said sleeve, said sleeve being providedwith a. slot inclined at an angle to the. axis of said shaftthere being ratchet teeth on said sleevealong the side of said slot nearersaid one. end of said sleeve, the-sleeve along the other sidevof said slot being smooth, a ratchet part on said weight and-extending. into saidslot, said partih'aving ratchet teeth along' its side nearer the.tooth-bearingside-of said slot, said part being smooth on its opposite side, and said ratchet partbeingof less width than said slot, whereby said ratchet part may move out of contact with said ratchet teeth of said slot when moving .away from said oneend.

4. The combination of claim 3, wherein said sleeve is mounted for rotativemovement relativeto said shaft, whereby bearing of the smooth side of said ratchet part against the smooth side of said slot, during movement of said'weight against the urge of said spring, may turn said sleeve.

LEWIS 'r. S'I'UM'PF. 

